So, I've been trying to setup multisite with no luck. It's definitey due to the changes being made to wp-config.
After some digging I think I might have found the issue.
Our current site uses https exclusively. So will our new one on a new domain/multisite install. I know about the domain mapping plugin. No worries there.
Do I need a Multi-Domain (UCC) BEFORE I try to set this up? That's not an issue to get. Just trying to confirm that's the problem.
Unfortunately, right now, in the middle of the day I can't mess with our site (I know - no staging - bad).